JP2013112234A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To tilt a vehicle body in a turning direction at an appropriate angle, maintain stability of a vehicle body, improve turning performance, prevent an occupant from feeling uncomfortable, and thereby achieve a stable traveling state, even when a wheel is locked during deceleration, by preventing unnecessary increase in steering angle.SOLUTION: A vehicle includes: the vehicle body having a steering part 11 and a body part 20 connected with each other; a steerable wheel 12F steering the vehicle body; a non-steerable wheel 12R; a steering device inputting the steering angle instruction; a vehicle speed sensor 54 detecting a vehicle speed; a tilting actuator device operating a link mechanism for tilting the steering part or the body part in the turning direction; and a steering actuator device 65 changing the steering angle of the steerable wheel based on the steering angle instruction. When a vehicle speed value detected by the vehicle speed sensor is abnormal, an appropriate vehicle speed is estimated to control the steering actuator device.

Description

  The present invention relates to a vehicle having at least a pair of left and right wheels.

  In recent years, in view of the problem of depletion of energy resources, there has been a strong demand for fuel saving of vehicles. On the other hand, the number of vehicle owners is increasing due to the low price of vehicles, and one person tends to own one vehicle. Therefore, for example, there is a problem that energy is wasted when only one driver drives a four-seater vehicle. The most efficient way to save fuel consumption by reducing the size of the vehicle is to configure the vehicle as a one-seater tricycle or four-wheel vehicle.

  However, depending on the running state, the stability of the vehicle may decrease. Therefore, a technique for improving the stability of the vehicle during turning by tilting the vehicle body in the lateral direction has been proposed (for example, see Patent Document 1).

JP 2008-155671 A

  However, in the conventional vehicle, in order to improve the turning performance, the vehicle body can be tilted inward in the turning direction. However, the tread is affected by the centrifugal force acting outward in the turning direction. When the vehicle is narrow, when the position of the center of gravity is high, or when the steering speed is high, the stability of the vehicle is likely to decrease, and the passenger may feel uncomfortable or feel uneasy.

  The present invention solves the problems of the conventional vehicle and prevents an unnecessary increase in the steering angle by correcting the value to an appropriate value when the value of the vehicle speed detected by the vehicle speed sensor is abnormal. Therefore, even when the wheel is locked during deceleration, the vehicle body can be tilted in the turning direction at an appropriate angle, so that the stability of the vehicle body can be maintained and the turning performance can be improved. An object of the present invention is to provide a highly safe vehicle that is capable of achieving a stable driving state without being uncomfortable for the occupant and having a good ride comfort.

  Therefore, in the vehicle of the present invention, a vehicle body including a steering unit and a main body unit that are connected to each other, a wheel that is rotatably attached to the steering unit, and a steerable steering wheel that steers the vehicle body, A non-steering wheel that is rotatably attached to the main body, is a steering device that inputs a steering angle command, a vehicle speed sensor that detects a vehicle speed, and turns the steering or main body. A link mechanism for tilting in the direction, a tilt actuator device for operating the link mechanism, a steering actuator device for changing a steering angle of the steered wheel based on a steering angle command input from the steering device, and the tilt A control device for controlling the actuator device for steering and the actuator device for steering, and when the vehicle speed value detected by the vehicle speed sensor is abnormal, the control device Estimating the vehicle speed based on the set deceleration beforehand predetermined limit value, the set gear ratio of the steering angle to the steering angle command, controls the steering actuator device.

  According to the configuration of the first aspect, even when the vehicle speed detected by the vehicle speed sensor is different from the actual vehicle speed, the steering angle can be appropriately controlled, so that the tread is narrow or the center of gravity is high. Even when the vehicle speed is high, the vehicle body can be tilted to the inside in the turning direction in a stable state to perform turning.

  According to the configuration of the second aspect, the abnormality in the vehicle speed detected by the vehicle speed sensor can be accurately determined, so that the steering angle can be appropriately controlled, and when the tread is narrow or the center of gravity is high. Even so, the stability of the vehicle body can be maintained.

  According to the structure of Claim 3, even if it is a case where a wheel locks during deceleration, a steering angle can be controlled appropriately.

It is a right view which shows the structure of the vehicle in embodiment of this invention. It is a figure which shows the structure of the link mechanism of the vehicle in embodiment of this invention. It is a rear view which shows the structure of the vehicle in embodiment of this invention. It is a block diagram which shows the structure of the vehicle body tilt control system in embodiment of this invention. It is a block diagram of a control system in an embodiment of the present invention. It is a figure which shows the dynamic model explaining the inclination operation | movement of the vehicle body at the time of turning driving | running | working in embodiment of this invention. It is a flowchart which shows the operation | movement of the lateral acceleration calculation process in embodiment of this invention. It is a figure which shows the model explaining the vehicle body link angle | corner in embodiment of this invention. It is a flowchart which shows the operation | movement of the link angular velocity estimation process in embodiment of this invention. It is a flowchart which shows the subroutine of the differentiation process of the yaw rate in embodiment of this invention. It is a flowchart which shows the subroutine of the filter process in embodiment of this invention. It is a flowchart which shows the operation | movement of the inclination control process in embodiment of this invention. It is a flowchart which shows the operation | movement of the link motor control process in embodiment of this invention. It is a figure explaining the steering angle in case the vehicle speed sensor value in embodiment of this invention is abnormal. It is a figure which shows the relationship between the vehicle speed and acceleration in embodiment of this invention. It is a figure which shows the vehicle speed calculated based on the acceleration correction value in embodiment of this invention. It is a figure explaining lateral acceleration by steering in an embodiment of the invention. It is a figure which shows the relationship between the variable reduction ratio and vehicle speed in embodiment of this invention. It is a flowchart which shows the operation | movement of the steering control process in embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a right side view showing a configuration of a vehicle in an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of a link mechanism of the vehicle in the embodiment of the present invention, and FIG. 3 is a vehicle in the embodiment of the present invention. It is a rear view which shows the structure. 3A is a diagram showing a state where the vehicle body is standing upright, and FIG. 3B is a diagram showing a state where the vehicle body is inclined.

  In the figure, reference numeral 10 denotes a vehicle according to the present embodiment, which includes a main body 20 as a vehicle body drive unit, a riding unit 11 as a steering unit on which an occupant gets on and steer, and a center in the width direction in front of the vehicle body. A wheel 12F as a steerable steering wheel which is a front wheel disposed on the left side, and a left wheel 12L and a right wheel 12R as non-steering wheels which are drive wheels disposed rearward as rear wheels and cannot be steered. And have. Furthermore, the vehicle 10 operates as a lean mechanism for leaning the vehicle body from side to side, that is, as a lean mechanism, that is, a vehicle body tilt mechanism, supporting the left and right wheels 12L and 12R, and the link mechanism 30. And a link motor 25 as a tilt actuator device. The vehicle 10 may be a three-wheeled vehicle with two front wheels on the left and right and one wheel on the rear, or may be a four-wheeled vehicle with two wheels on the left and right. As shown in the figure, a case will be described in which the front wheel is a single wheel and the rear wheel is a left and right tricycle. Further, although the steered wheel may function as a drive wheel, in the present embodiment, the description will be made assuming that the steered wheel does not function as a drive wheel.

  When turning, the angle of the left and right wheels 12L and 12R with respect to the road surface 18, that is, the camber angle is changed, and the vehicle body including the riding portion 11 and the main body portion 20 is inclined toward the turning inner wheel, thereby improving turning performance and the occupant. It is possible to ensure the comfort of the car. That is, the vehicle 10 can tilt the vehicle body in the lateral direction (left and right direction). In the example shown in FIGS. 2 and 3 (a), the left and right wheels 12L and 12R are upright with respect to the road surface 18, that is, the camber angle is 0 degree. In the example shown in FIG. 3B, the left and right wheels 12L and 12R are inclined in the right direction with respect to the road surface 18, that is, a camber angle is given.

  The link mechanism 30 includes a left vertical link unit 33L that supports a left wheel 12L and a left rotation driving device 51L including an electric motor that applies driving force to the wheel 12L, a right wheel 12R, and the wheel 12R. A right vertical link unit 33R that supports a right rotation drive device 51R composed of an electric motor or the like that applies a driving force to an upper side, and an upper horizontal link unit 31U that connects the upper ends of the left and right vertical link units 33L and 33R; The lower horizontal link unit 31D that connects the lower ends of the left and right vertical link units 33L and 33R, and the central vertical member 21 that has an upper end fixed to the main body 20 and extends vertically. The left and right vertical link units 33L and 33R and the upper and lower horizontal link units 31U and 31D are rotatably connected. Further, the upper and lower horizontal link units 31U and 31D are rotatably connected to the central vertical member 21 at the center thereof. When the left and right wheels 12L and 12R, the left and right rotational drive devices 51L and 51R, the left and right vertical link units 33L and 33R, and the upper and lower horizontal link units 31U and 31D are described in an integrated manner, The rotation drive device 51, the vertical link unit 33, and the horizontal link unit 31 will be described.

  The rotational drive device 51 as a drive motor is a so-called in-wheel motor, and a rotating shaft as a rotor is fixed to the vertical link unit 33 and a body as a stator is rotatably attached to the body. Is connected to the shaft of the wheel 12, and the wheel 12 is rotated by the rotation of the rotating shaft. The rotational drive device 51 may be a motor other than an in-wheel motor.

  The link motor 25 is a rotary electric actuator including an electric motor or the like, and includes a cylindrical body as a stator and a rotating shaft as a rotor rotatably attached to the body. The body is fixed to the main body portion 20 via the mounting flange 22, and the rotating shaft is fixed to the lateral link unit 31 </ b> U on the upper side of the link mechanism 30. The rotation axis of the link motor 25 functions as an inclination axis for inclining the main body 20 and is coaxial with the rotation axis of the connecting portion between the central vertical member 21 and the upper horizontal link unit 31U. When the link motor 25 is driven to rotate the rotation shaft with respect to the body, the upper horizontal link unit 31U rotates with respect to the main body 20 and the central vertical member 21 fixed to the main body 20, The link mechanism 30 operates, that is, bends and stretches. Thereby, the main-body part 20 can be inclined. Note that the rotation axis of the link motor 25 may be fixed to the main body 20 and the central vertical member 21, and the body may be fixed to the upper horizontal link unit 31U.

  The link motor 25 includes a link angle sensor 25 a that detects a change in the link angle of the link mechanism 30. The link angle sensor 25a is a rotation angle sensor that detects the rotation angle of the rotation shaft with respect to the body in the link motor 25, and includes, for example, a resolver, an encoder, and the like. As described above, when the link motor 25 is driven to rotate the rotation shaft with respect to the body, the upper horizontal link unit 31U rotates with respect to the main body 20 and the central vertical member 21 fixed to the main body 20. Therefore, a change in the angle of the upper horizontal link unit 31U relative to the central vertical member 21, that is, a change in the link angle can be detected by detecting the rotation angle of the rotation shaft with respect to the body.

  The link motor 25 includes a lock mechanism (not shown) that fixes the rotation shaft to the body so as not to rotate. The lock mechanism is a mechanical mechanism, and preferably does not consume electric power while the rotation shaft is fixed to the body so as not to rotate. The lock mechanism can fix the rotation shaft so as not to rotate at a predetermined angle with respect to the body.

  The riding part 11 is connected to the front end of the main body part 20 via a connecting part (not shown). The connecting part may have a function of connecting the riding part 11 and the main body part 20 so as to be relatively displaceable in a predetermined direction.

  The boarding part 11 includes a seat 11a, a footrest 11b, and a windbreak part 11c. The seat 11 a is a part for a passenger to sit while the vehicle 10 is traveling. The footrest 11b is a part for supporting the occupant's foot, and is disposed on the front side (right side in FIG. 1) and below the seat 11a.

  Further, a battery device (not shown) is disposed behind or below the riding section 11 or on the main body section 20. The battery device is an energy supply source for the rotation drive device 51 and the link motor 25. In addition, a control device, an inverter device, various sensors, and the like (not shown) are accommodated in the rear portion or the lower portion of the riding portion 11 or in the main body portion 20.

  A steering device 41 is disposed in front of the seat 11a. The steering device 41 is operated by an occupant to input steering command information such as a steering direction and a steering angle. A steering bar 41a as a steering device, a meter such as a speed meter, an indicator, a switch, and an acceleration command for inputting an acceleration command. Members necessary for steering such as a throttle lever as an input means and a brake lever as a deceleration command input means for inputting a deceleration command are provided. The occupant operates the handle bar 41a and other members to instruct the traveling state of the vehicle 10 (for example, traveling direction, traveling speed, turning direction, turning radius, etc.). As the steering device, other devices such as a steering wheel, a jog dial, a touch panel, and a push button can be used instead of the handle bar 41a.

  The wheel 12F is connected to the riding section 11 via a front wheel fork 17 that is a part of a suspension device (suspension device). The suspension device is a device similar to a suspension device for front wheels used in, for example, general motorcycles, bicycles, and the like, and the front wheel fork 17 is, for example, a telescopic type fork with a built-in spring. Then, as in the case of a general motorcycle, bicycle, etc., the wheel 12F as the steering wheel changes the steering angle in accordance with the operation of the handlebar 41a by the occupant, thereby changing the traveling direction of the vehicle 10.

  Specifically, the handle bar 41a is connected to the upper end of a steering shaft member (not shown), and the upper end of the steering shaft member is rotatably attached to a frame member (not shown) provided in the riding section 11. The steering shaft member is attached to the frame member in an obliquely inclined state so that the upper end is located behind the lower end. Then, the rotation angle with respect to the frame member at the upper end of the steering shaft member, that is, the steering wheel angle as the steering angle command inputted by the occupant operating the steering bar 41a is detected by the steering wheel angle sensor 62 as the input steering angle detection means. Is done. The handle angle sensor 62 includes, for example, an encoder.

A steering motor 65 as a steering actuator device is disposed between the upper end and the lower end of the steering shaft member, and the steering motor 65 has a handle angle detected by the handle angle sensor 62. Based on this, the lower end of the steering shaft member is rotated. The lower end of the steering shaft member is rotatably attached to the frame member and is connected to the upper end of the front wheel fork 17. The rotation angle of the lower end of the steering shaft member relative to the frame member, that is, the steering angle output from the steering motor 65 and transmitted to the wheel 12F via the front wheel fork 17 is the steering angle as output steering angle detection means. It is detected by the sensor 63. The steering angle sensor 63 is, for example, a rotation angle sensor that detects the rotation angle of the rotation shaft with respect to the body in the steering motor 65, and includes a resolver, an encoder, and the like. The distance between the left and right wheels 12L and 12R axle is the axle and the rear wheel of the wheel 12F is a front wheel, i.e., the wheel base is L _H.

  Further, a vehicle speed sensor 54 as vehicle speed detecting means for detecting the vehicle speed as the traveling speed of the vehicle 10 is disposed on the lower end of the front wheel fork 17 that supports the axle of the wheel 12F or the axle of the left and right wheels 12L and 12R. Yes. The vehicle speed sensor 54 is a sensor that detects the vehicle speed based on the rotational speed of the wheels 12F, 12L, or 12R, and includes, for example, an encoder.

  In the present embodiment, the vehicle 10 has a lateral acceleration sensor 44. The lateral acceleration sensor 44 is a sensor composed of a general acceleration sensor, a gyro sensor, or the like, and detects the lateral acceleration of the vehicle 10, that is, the acceleration in the lateral direction (horizontal direction in FIG. 3) as the width direction of the vehicle body. To do.

  Since the vehicle 10 is stabilized by inclining the vehicle body toward the inside of the turn at the time of turning, the vehicle 10 is controlled so that the centrifugal force to the outside of the turn at the time of turning and the gravity are balanced by turning the vehicle body. By performing such control, for example, even if the road surface 18 is inclined in a direction perpendicular to the traveling direction (left and right direction with respect to the traveling direction), the vehicle body can always be kept horizontal. As a result, the vehicle body and the occupant are apparently always subjected to gravity downward in the vertical direction, the sense of incongruity is reduced, and the stability of the vehicle 10 is improved.

  Therefore, in the present embodiment, in order to detect the lateral acceleration of the leaning vehicle body, the lateral acceleration sensor 44 is attached to the vehicle body, and feedback control is performed so that the output of the lateral acceleration sensor 44 becomes zero. As a result, the vehicle body can be tilted to an inclination angle at which the centrifugal force acting during turning and gravity are balanced. Further, even when the road surface 18 is inclined in a direction perpendicular to the traveling direction, the vehicle body can be controlled to have an inclination angle that makes the vehicle body vertical. The lateral acceleration sensor 44 is disposed so as to be positioned at the center in the width direction of the vehicle body, that is, on the longitudinal axis of the vehicle body.

  However, if there is one lateral acceleration sensor 44, an unnecessary acceleration component may be detected. For example, while the vehicle 10 is traveling, only one of the left and right wheels 12L and 12R may fall into the depression on the road surface 18. In this case, since the vehicle body is tilted, the lateral acceleration sensor 44 is displaced in the circumferential direction and detects the acceleration in the circumferential direction. That is, an acceleration component that is not directly derived from centrifugal force or gravity, that is, an unnecessary acceleration component is detected.

  In addition, the vehicle 10 includes a portion that functions as a spring and has elasticity like the tire portions of the left and right wheels 12 </ b> L and 12 </ b> R. For this reason, the lateral acceleration sensor 44 is considered to be attached to the vehicle body through inevitable play and springs, and therefore acceleration generated by the displacement of the play and springs is also detected as an unnecessary acceleration component.

  Such an unnecessary acceleration component may deteriorate the controllability of the vehicle body tilt control system. For example, if the control gain of the vehicle body tilt control system is increased, control system vibration, divergence, and the like due to unnecessary acceleration components occur, so that it is not possible to increase the control gain even if responsiveness is to be improved. .

  Therefore, in the present embodiment, a plurality of lateral acceleration sensors 44 are provided at different heights. In the example shown in FIGS. 1 and 3, there are two lateral acceleration sensors 44, a first lateral acceleration sensor 44a and a second lateral acceleration sensor 44b, which are a first lateral acceleration sensor 44a and a second lateral acceleration sensor 44b. Are arranged at different height positions. By appropriately selecting the positions of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b, unnecessary acceleration components can be effectively removed.

Specifically, as shown in FIG. 3 (a), the first lateral acceleration sensor 44a is in the back of the riding section 11, the distance from the road surface 18, i.e., is disposed at the position of L ₁ Height ing. The second lateral acceleration sensor 44b is the upper surface of the rear or body portion 20 of the riding portion 11, the distance from the road surface 18, i.e., is disposed at a position of L ₂ height. Note that L ₁ > L ₂ . When turning, when the vehicle is turned with the vehicle body tilted inward (right side in the drawing) as shown in FIG. 3B, the first lateral acceleration sensor 44a detects the lateral acceleration. The detection value a ₁ is output, and the second lateral acceleration sensor 44b detects the lateral acceleration and outputs the detection value a ₂ . Although the center of the tilting motion when the vehicle body tilts, that is, the roll center, is strictly located slightly below the road surface 18, it is considered that the center is substantially equal to the road surface 18 in practice.

It is desirable that both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b are attached to a sufficiently rigid member. Further, if the difference between L ₁ and L ₂ is small, the difference between the detection values a ₁ and a ₂ is small. Therefore, it is desirable that the difference be sufficiently large, for example, 0.3 [m] or more. Furthermore, it is desirable that both the first lateral acceleration sensor 44 a and the second lateral acceleration sensor 44 b are disposed above the link mechanism 30. Further, when the vehicle body is supported by a spring such as a suspension, it is desirable that both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b are arranged on a so-called “spring top”. Further, both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b may be disposed between the axle of the front wheel 12F and the axles of the left and right wheels 12L and 12R as rear wheels. desirable. Furthermore, it is desirable that both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b are disposed as close to the occupant as possible. Further, both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b are preferably located on the central axis of the vehicle body extending in the traveling direction when viewed from above, that is, not offset with respect to the traveling direction. .

  In the present embodiment, a roll rate sensor 44c for detecting the angular velocity of the tilting motion of the vehicle body and a yaw rate sensor 44d as a yaw angular velocity detecting means for detecting the angular velocity of the turning motion of the vehicle body, that is, the yaw angular velocity of the vehicle body are arranged. It is installed. Specifically, it is desirable that both the roll rate sensor 44c and the yaw rate sensor 44d are located on the central axis of the vehicle body extending in the traveling direction when viewed from above, that is, not offset with respect to the traveling direction. It is arranged between the seat 11a and the footrest 11b.

  The roll rate sensor 44c is a general roll rate sensor, and for example, a gyro sensor is attached so as to detect a rotational angular velocity in a plane perpendicular to the road surface 18. . The yaw rate sensor 44d is a general yaw rate sensor, and for example, a gyro sensor is attached so as to detect a rotational angular velocity in a plane parallel to the road surface 18. Note that the three-dimensional gyro sensor can exhibit the functions of the roll rate sensor 44c and the yaw rate sensor 44d. That is, the roll rate sensor 44c and the yaw rate sensor 44d may be configured separately or may be configured integrally.

  The vehicle 10 in the present embodiment has a vehicle body tilt control system as a part of the control device. The vehicle body tilt control system is a kind of computer system, and includes a tilt control device, a steering control device, and a drive control device including an ECU (Electronic Control Unit). The tilt control device includes arithmetic means such as a processor, storage means such as a magnetic disk and a semiconductor memory, an input / output interface, and the like, and includes a link angle sensor 25a, a first lateral acceleration sensor 44a, a second lateral acceleration sensor 44b, a roll rate. The sensor 44c, the yaw rate sensor 44d, the vehicle speed sensor 54, and the link motor 25 are connected. Then, the tilt control device outputs a torque command value for operating the link motor 25. Further, the steering control device includes a calculation means such as a processor, a storage means such as a magnetic disk and a semiconductor memory, an input / output interface, and the like, and is connected to a handle angle sensor 62, a steering angle sensor 63, a vehicle speed sensor 54, and a steering motor 65. Has been. Further, the drive control device includes a calculation unit such as a processor, a storage unit such as a magnetic disk and a semiconductor memory, an input / output interface, and the like, and is connected to a brake sensor 58, a throttle sensor 59, and a rotary drive unit 51 which will be described later. Yes. The steering control device outputs a control pulse for operating the steering motor 65. The tilt control device and the steering control device are connected to each other. In addition, the tilt control device, the steering control device, and the drive control device are not necessarily configured separately, and may be configured integrally.

  The tilt control device performs feedback control and feedforward control during turning, so that the tilt angle of the vehicle body is such that the lateral acceleration value detected by the lateral acceleration sensor 44 becomes an angle that becomes zero. The motor 25 is operated. That is, the tilt angle of the vehicle body is controlled so that the centrifugal force to the outside of the turn balances with the gravity and the lateral acceleration component becomes zero. As a result, a force in a direction parallel to the longitudinal axis of the vehicle body acts on the vehicle body and the occupant on the riding section 11. Therefore, the stability of the vehicle body can be maintained and the turning performance can be improved.

  Also, when a disturbance in the tilt direction is received, a part due to the disturbance in the change in the tilt angle of the vehicle body is extracted, and for the remaining part, the tilt angle of the vehicle body is controlled in the normal mode, and the extracted part In contrast, the vehicle body tilt angle is controlled in the disturbance response mode. Therefore, the stability of the vehicle body can be maintained even when subjected to disturbance. In addition, the rider does not feel discomfort and the ride comfort is improved.

  Further, in the present embodiment, the steering angle command input by the occupant operating the handle bar 41a is reduced according to the vehicle speed and the leaning state of the vehicle body to control the steering angle of the wheel 12F. More specifically, a variable reduction ratio as a steering reduction ratio is set based on the vehicle speed and the link angle of the link mechanism 30 for tilting the vehicle body, and a steering motor as a steering actuator device is set according to the variable reduction ratio. The steering angle target value of the wheel 12F as the steering wheel 65 to be changed is reduced with respect to the steering angle sensor value as the input steering angle command.

  The variable reduction ratio is controlled according to the vehicle speed so that the link angle does not exceed a preset link angle limit value. Further, the variable reduction ratio is determined so as to increase as the vehicle speed increases.

  Further, when the value of the vehicle speed detected by the vehicle speed sensor 54 is abnormal, the vehicle speed is estimated based on the deceleration set to a predetermined limit value, and the steering angle of the wheel 12F is controlled. More specifically, the steering angle target value of the wheel 12F is set based on the vehicle speed calculated from the differential value of the vehicle speed corrected so as to be within a predetermined range.

  As a result, even when one or more of the wheels 12F, 12L and 12R are locked during deceleration, even if the vehicle speed detected by the vehicle speed sensor is different from the actual vehicle speed, it approximates the actual vehicle speed. Since the variable reduction ratio according to the vehicle speed can be set, the steering angle target value of the wheel 12F does not become unnecessarily large, and the stability of the vehicle 10 does not deteriorate.

  When vehicle body tilt control is performed without performing such steering control, for example, when one or more of the wheels 12F, 12L, and 12R are locked during deceleration, the vehicle speed sensor detects a vehicle speed lower than the actual vehicle speed. As a result, the steering angle target value of the wheel 12F may be set unnecessarily large according to the low vehicle speed, and the stability of the vehicle 10 may be reduced.

  In contrast, in the present embodiment, the differential value of the vehicle speed detected by the vehicle speed sensor 54 is corrected so as to be within a predetermined range set in advance, and based on the vehicle speed calculated from the corrected differential value of the vehicle speed. Since the steering angle target value of the wheel 12F is set, the steering angle of the wheel 12F is set to an appropriate value, and the vehicle body can be tilted inward in the turning direction in a stable state to perform turning.

  Next, the configuration of the vehicle body tilt control system will be described.

  FIG. 4 is a block diagram showing the configuration of the vehicle body tilt control system in the embodiment of the present invention.

  In the figure, 46 is an inclination control ECU as an inclination control device, and includes a link angle sensor 25a, a first lateral acceleration sensor 44a, a second lateral acceleration sensor 44b, a roll rate sensor 44c, a yaw rate sensor 44d, a vehicle speed sensor 54, and a link motor. 25. The tilt control ECU 46 includes a lateral acceleration calculation unit 48, a link angular velocity estimation unit 50, a disturbance calculation unit 43, a tilt control unit 47, and a link motor control unit 42.

  Reference numeral 61 denotes a steering control ECU as a steering control device, which is connected to a handle angle sensor 62, a steering angle sensor 63, a vehicle speed sensor 54, and a steering motor 65. The steering control ECU 61 includes a steering control unit 66 and a steering motor control unit 67.

  Reference numeral 55 denotes a drive control ECU as a drive control device, which is connected to a brake sensor 58, a throttle sensor 59, and a rotary drive device 51 as a drive motor. The drive control ECU 55 includes a drive control unit 56 and a drive motor control unit 57.

  Here, the lateral acceleration calculation unit 48 calculates a combined lateral acceleration based on the lateral acceleration detected by the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b. The link angular velocity estimation unit 50 calculates a link angular velocity prediction value based on the yaw rate as the yaw angular velocity detected by the yaw rate sensor 44d and the vehicle speed detected by the vehicle speed sensor 54. Further, the disturbance calculation unit 43 calculates a roll rate for the disturbance based on the roll rate as the angular velocity of the tilting motion of the vehicle body detected by the roll rate sensor 44c and the link angle detected by the link angle sensor 25a.

  The tilt controller 47 is based on the combined lateral acceleration calculated by the lateral acceleration calculator 48, the predicted link angular velocity calculated by the link angular velocity estimator 50, and the disturbance roll rate calculated by the disturbance calculator 43. Then, the speed command value as the control value is calculated and output. Further, the link motor control unit 42 outputs a torque command value as a control value for operating the link motor 25 based on the speed command value output from the inclination control unit 47.

  The steering control unit 66 calculates and outputs a steering wheel steering angle command value as a control value based on the steering wheel angle detected by the steering wheel angle sensor 62 and the vehicle speed detected by the vehicle speed sensor 54. The steering motor control unit 67 is a control pulse as a control value for operating the steering motor 65 based on the steering angle detected by the steering angle sensor 63 and the steering wheel steering angle command value output by the steering control unit 66. Is output.

  Further, the drive control unit 56 controls the control value based on the deceleration command value as the brake lever operation amount detected by the brake sensor 58 and the acceleration command value as the throttle lever operation amount detected by the throttle sensor 59. The drive command value is calculated and output. The drive motor control unit 57 outputs a torque command value as a control value for operating the rotary drive device 51 based on the drive command value output by the drive control unit 56.

  Next, the operation of the vehicle 10 configured as described above will be described. First, the operation of the lateral acceleration calculation process, which is a part of the operation of the vehicle body tilt control process in turning, will be described.

  FIG. 5 is a block diagram of the control system in the embodiment of the present invention, FIG. 6 is a diagram showing a dynamic model for explaining the leaning operation of the vehicle body during turning traveling in the embodiment of the present invention, and FIG. 7 is an embodiment of the present invention. It is a flowchart which shows the operation | movement of the lateral acceleration calculation process in the form.

  In the vehicle body tilt control process according to the present embodiment, control in which tilt control by the tilt control ECU 46 and steering control by the steering control ECU 61 are combined as shown in FIG. 5 is performed. Note that the tilt control by the tilt control ECU 46 is a combination of feedback control and feedforward control.

In FIG. 5, f ₁ is a transfer function represented by Equation (6) described later, G _P , G _RP, and G _YD are control gains of the proportional control operation, LPF is a low-pass filter, and s is It is a differential element. Further, f ₂ is a link angular velocity prediction value expressed by the following formula (10), and f ₃ is a roll rate gain.

  When turning is started, the vehicle body tilt control system starts the vehicle body tilt control process. By performing posture control, the vehicle 10 turns with the link mechanism 30 in a state where the vehicle body is tilted inward (right side in the drawing) as shown in FIG. Further, during turning, a centrifugal force to the outside of the turning acts on the vehicle body, and a lateral component of gravity is generated by tilting the vehicle body to the inside of the turn. Then, the lateral acceleration calculation unit 48 executes a lateral acceleration calculation process, calculates a combined lateral acceleration a, and outputs it to the tilt control unit 47. Then, the inclination control unit 47 performs feedback control, and outputs a speed command value as a control value such that the value of the combined lateral acceleration a becomes zero. Then, the link motor control unit 42 outputs a torque command value to the link motor 25 based on the speed command value output from the inclination control unit 47.

The vehicle body tilt control process is a process that is repeatedly executed by the vehicle body tilt control system at a predetermined control cycle T _S (for example, 5 [ms]) while the vehicle 10 is turned on. This is a process for improving turning performance and ensuring passenger comfort.

  In FIG. 6, 44A is a first sensor position indicating the position where the first lateral acceleration sensor 44a is disposed on the vehicle body, and 44B is a first position indicating the position where the second lateral acceleration sensor 44b is disposed on the vehicle body. Two sensor positions.

The acceleration detected by the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b and outputting the detected value is <1> centrifugal force acting on the vehicle body when turning, and <2> tilting the vehicle body toward the inside of the turn. The lateral component of the generated gravity, <3> the first lateral acceleration sensor 44a and the like due to the inclination of the vehicle body, the backlash or the displacement of the spring, etc., when only one of the left and right wheels 12L and 12R falls into the depression of the road surface 18; The acceleration generated by the displacement of the second lateral acceleration sensor 44b in the circumferential direction, and the <4> operation of the link motor 25 or the reaction thereof causes the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b to be displaced in the circumferential direction. It is considered that there are four accelerations caused by this. Of these four acceleration, the <1> and <2>, the height of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b, that is, independent of L ₁ and L _2. On the other hand, since <3> and <4> are accelerations generated by displacement in the circumferential direction, they are proportional to the distance from the roll center, that is, roughly proportional to L ₁ and L ₂ .

Here, the acceleration of the <3> of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b outputs the detected value detected by the a _X1 and a _X2, a first lateral acceleration sensor 44a and a second lateral acceleration The acceleration of <4>, which is detected by the sensor 44b and outputs the detected value, is a _M1 and a _M2 . Further, the acceleration of <1> to the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b outputs the detected value detected by the a _T, a first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b is detected Then, the acceleration of <2> that outputs the detected value is defined as a _G. Since <1> and <2> are irrelevant to the heights of the first and second lateral acceleration sensors 44a and 44b, the detection values of the first and second lateral acceleration sensors 44a and 44b are equal. .

Then, only one of the left and right wheels 12L and 12R are inclined in the vehicle body due to the fall in a recess of a road surface 18, the angular velocity omega _R the circumferential direction of displacement by the displacement or the like of Gataya spring, the angular acceleration omega _{Let R} '. Further, the angular velocity of the circumferential displacement due to the operation of the link motor 25 or its reaction is ω _M , and the angular acceleration is ω _M ′. The angular velocity ω _M or the angular acceleration ω _M ′ can be obtained from the detection value of the link angle sensor 25a.

Then, a _X1 = L ₁ ω _R ′, a _X2 = L ₂ ω _R ′, a _M1 = L ₁ ω _M ′, a _M2 = L ₂ ω _M ′.

Further, when the detection value of the acceleration by the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b is detecting and outputting the a ₁ and a _2, a ₁ and a _2, four acceleration <1> to <4 It is represented by the following formulas (1) and (2).
_{a 1 = a T + a G} + L 1 ω R '+ L 1 ω M' ··· formula (1)
_{a 2 = a T + a G} + L 2 ω R '+ L 2 ω M' ··· formula (2)
Then, by subtracting equation (2) from equation (1), the following equation (3) can be obtained.
a ₁ −a ₂ = (L ₁ −L ₂ ) ω _R ′ + (L ₁ −L ₂ ) ω _M ′ Equation (3)
Here, the values of L ₁ and L ₂ are known because they are the heights of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b. The value of ω _M ′ is known because it is a differential value of the angular velocity ω _M of the link motor 25. Then, on the right side of the equation (3), only the value of ω _R ′ of the first term is unknown, and all other values are known. Therefore, the value of ω _R ′ can be obtained from the detection values a ₁ and a _{2 of} the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b. That is, unnecessary acceleration components can be removed based on the detection values a ₁ and a ₂ of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b.

When the vehicle body tilt control system starts the vehicle body tilt control process, the lateral acceleration calculation unit 48 starts the lateral acceleration calculation process, and first acquires the first lateral acceleration sensor value a ₁ (step S1) and the second lateral acceleration calculation process. An acceleration sensor value a ₂ is acquired (step S2). Then, the lateral acceleration calculation unit 48 calculates the acceleration difference Δa (step S3). The Δa is expressed by the following equation (4).
Δa = a ₁ −a ₂ Formula (4)
Then, the lateral acceleration calculation unit 48 performs ΔL call (step S4), and performs the L ₂ call (step S5). The ΔL is expressed by the following equation (5).
ΔL = L ₁ −L ₂ Formula (5)
Subsequently, the lateral acceleration calculation unit 48 calculates a combined lateral acceleration a (step S6). Incidentally, the synthetic lateral acceleration a lateral acceleration sensor 44 is a value corresponding to the lateral acceleration sensor value a when the one, first lateral acceleration sensor value a ₁ and the second lateral acceleration sensor value a ₂ Is obtained by the following equations (6) and (7).
a = a ₂ − (L ₂ / ΔL) Δa (6)
a = a ₁ − (L ₁ / ΔL) Δa (7)
Theoretically, the same value can be obtained by both equation (6) and equation (7), but since the acceleration caused by the circumferential displacement is proportional to the distance from the roll center, in practice, the roll center It is desirable to use a ₂ which is a detection value of the lateral acceleration sensor 44 closer to the second lateral acceleration sensor 44b as a reference. Therefore, in the present embodiment, the combined lateral acceleration a is calculated by Expression (6).

  Finally, the lateral acceleration calculation unit 48 sends the combined lateral acceleration a to the tilt control unit 47 (step S7), and ends the lateral acceleration calculation process.

Thus, in this embodiment, a first lateral acceleration sensor 44a and a second lateral acceleration sensor 44b is placed in different height positions, a first lateral acceleration sensor value a ₁ and the second lateral acceleration sensor A combined lateral acceleration a obtained by combining the value a ₂ is calculated, and feedback control is performed so that the value of the combined lateral acceleration a becomes zero to control the tilt angle of the vehicle body.

  As a result, unnecessary acceleration components can be removed, so that it is not affected by road surface conditions, the occurrence of vibrations and divergence of the control system can be prevented, and the control gain of the vehicle body tilt control system is increased. Control responsiveness can be improved.

  In the present embodiment, the case where there are two lateral acceleration sensors 44 has been described. However, if there are a plurality of lateral acceleration sensors 44 arranged at different heights, the number of lateral acceleration sensors 44 is three or more. There may be any number.

  Next, the operation of the link angular velocity estimation process for estimating the link angular velocity in turning travel will be described.

  FIG. 8 is a diagram showing a model for explaining the vehicle body link angle in the embodiment of the present invention, FIG. 9 is a flowchart showing the operation of link angular velocity estimation processing in the embodiment of the present invention, and FIG. 10 is an embodiment of the present invention. FIG. 11 is a flowchart showing a subroutine of the filter process in the embodiment of the present invention.

  When the link angular velocity estimation unit 50 starts the link angular velocity estimation process, the link angular velocity estimation unit 50 first acquires a yaw rate sensor value ψ that is a yaw rate value detected by the yaw rate sensor 44d (step S11), and a vehicle speed value detected by the vehicle speed sensor 54. The vehicle speed sensor value ν is obtained (step S12).

  Then, the link angular velocity estimation unit 50 performs yaw rate differentiation processing (step S13) and calculates Δψ. The Δψ is a value obtained by differentiating the yaw rate with time, and corresponds to the yaw angular acceleration.

In the yaw rate differentiation process, the link angular velocity estimation unit 50 first makes a ψ _old call (step S13-1). Note that ψ _old is the value of ψ (t) saved when the previous vehicle body tilt control process was executed. In the initial setting, ψ _old = 0.

Subsequently, the link angular velocity estimation unit 50 acquires a control cycle T _S (step S13-2).

Subsequently, the link angular velocity estimation unit 50 calculates the yaw rate differential value Δψ (step S13-3). Δψ is calculated by the following equation (8).
Δψ = (ψ (t) −ψ _old ) / T _S (8)
The link angular velocity estimation unit 50 stores ψ _old = ψ (t) (step S13-4), and ends the yaw rate differentiation process.

  Subsequently, the link angular velocity estimation unit 50 performs a filtering process on the yaw rate differential value Δψ (step S14).

In the filter processing, the link angular velocity estimation unit 50 first acquires a control cycle T _S (step S14-1).

  Subsequently, the link angular velocity estimation unit 50 acquires a cutoff frequency w (step S14-2).

Subsequently, the link angular velocity estimation unit 50 performs a Δψ _old call (step S14-3). Note that Δψ _old is a value of Δψ (t) saved when the previous vehicle body tilt control process was executed.

Subsequently, the link angular velocity estimation unit 50 calculates the filtered yaw rate differential value Δψ (t) (step S14-4). Δψ (t) is calculated by the following equation (9).
_{Δψ (t) = Δψ old /} (1 + T S w) + T S wψ / (1 + T S w) ··· (9)
The expression (9) is an expression of an IIR (Infinite Impulse Response) filter generally used as a bandpass filter, but a first-order lag low-pass filter may be simply used. As the IIR filter, for example, a Chebyshev type II filter may be used, or another filter may be used. Further, a generally used FIR (Finite Impulse Response) filter may be used. Furthermore, the cut-off frequency (−3 [dB] frequency) of the band pass filter is preferably 10 [Hz] or less, and more preferably several [Hz].

Then, the link angular velocity estimation unit 50 stores it as Δψ _old = Δψ (t) (step S14-5), and ends the filter process. That is, the value of Δψ (t) calculated at the time of execution of the current vehicle body tilt control process is stored in the storage unit as Δψ _old .

Subsequently, the link angular velocity estimation unit 50 calculates a link angular velocity prediction value f ₂ (step S15). Here, assuming that gravity is g, the link angular velocity predicted value f ₂ is calculated by the following equation (10).
f ₂ = dη / dt = (ν / g) (dψ / dt) (10)
As described above, the link angle sensor 25a detects a change in the angle of the upper horizontal link unit 31U with respect to the central vertical member 21, that is, a change in the link angle. Here, it is assumed that the link angle sensor value, that is, the link angle is η, and the inclination angle of the vehicle body at the time of turning is controlled so that the centrifugal force a ₀ as the lateral acceleration and the gravity g are balanced. If 18 is horizontal, the centrifugal force a ₀ and the gravity g are as shown in FIG. 8, and the relationship represented by the following formula (11) is present between the centrifugal force a ₀ and the gravity g. To establish.
a ₀ cos η = gsin η (11)
From the equation (11), the following equation (12) is derived.
a ₀ / g = sin η / cos η = tan η (12)
Further, the following equation (13) is derived from the equation (12).
a ₀ = g tan η (13)
On the other hand, assuming that the yaw rate sensor value, that is, the yaw rate is ψ, and the turning radius is r, the vehicle speed sensor value, that is, the vehicle speed ν and the centrifugal force a ₀ as the lateral acceleration acting on the vehicle body at the time of turning are It is represented by (14) and (15).
ν = rψ Equation (14)
a ₀ = rψ ² = νψ (15)
Then, the following equation (16) is derived from the equation (15) and the equation (13).
tan η = νψ / g (16)
Furthermore, it can be approximated as tan η≈η, and the change in the vehicle speed ν is sufficiently slow compared to the change in the link angle η, so that the vehicle speed ν can be regarded as a constant. From the above, the formula (10) can be obtained.

Subsequently, the link angular velocity estimation unit 50 calculates a link angular velocity control value a _f (step S16). The link angular velocity control value _af is calculated by the following equation (17).
a _f = Adη / dt (17)
Here, A is an arbitrary value of 0 to 1, and is a tuning constant determined according to the structure of the vehicle 10.

Finally, the link angular velocity estimation unit 50 sends the link angular velocity control value a _f to the inclination control unit 47 (step S17), and ends the link angular velocity estimation process.

  Next, the operation of the inclination control process for outputting the speed command value to the link motor control unit 42 will be described.

  FIG. 12 is a flowchart showing the operation of the tilt control process in the embodiment of the present invention.

  In the tilt control process, the tilt control unit 47 first receives the combined lateral acceleration a from the lateral acceleration calculation unit 48 (step S21).

Subsequently, the inclination control unit 47 makes an _old call (step S22). a _old is the combined lateral acceleration a stored when the vehicle body tilt control process is executed last time. In the initial setting, a _old = 0.

Subsequently, the inclination control unit 47 acquires the control cycle T _S (step S23), and calculates the differential value of a (step S24). Here, when the differential value of a is da / dt, the da / dt is calculated by the following equation (18).
da / dt = (a−a _old ) / T _S (18)
And the inclination control part 47 is preserve | saved as _aold = a (step S25). That is, the lateral acceleration sensor value a acquired at the time of execution of the current vehicle body tilt control process is stored as a _old in the storage unit.

Then, tilt control unit 47 calculates the first control value U _P (step S26). Here, if the control gain of the proportional control operation, that is, the proportional gain is _GP , the first control value _UP is calculated by the following equation (19).
U _P = G _P a ··· (19)
Then, tilt control unit 47 calculates the second control value U _D (step S27). Here, if the control gain of the differential control operation, that is, the differential time is G _D , the second control value U _D is calculated by the following equation (20).
U _D = G _D da / dt (20)
Subsequently, the inclination control unit 47 calculates a third control value U (step S28). Third control value U is the sum of the first control value U _P and the second control value U _D, is calculated by the following equation (21).
U = U _P + U _D ··· formula (21)
When the third control value U is calculated, the inclination control unit 47 receives the link angular velocity control value a _f from the link angular velocity estimation unit 50 (step S29).

Subsequently, the inclination control unit 47 calculates a fourth control value U (step S30). The fourth control value U is the sum of the third control value U and the link angular velocity control value _af, and is calculated by the following equation (22).
U = U + a _f Expression (22)
Finally, the tilt control unit 47 outputs the fourth control value U as a speed command value to the link motor control unit 42 (step S31), and ends the tilt control process.

  Next, the operation of the link motor control process for outputting a torque command value to the link motor 25 will be described.

  FIG. 13 is a flowchart showing the operation of the link motor control process in the embodiment of the present invention.

  In the link motor control process, the link motor control unit 42 first receives the fourth control value U from the inclination control unit 47 (step S41).

Subsequently, the link motor control unit 42 calculates a link motor control value as a torque command value for operating the link motor 25 (step S42). Here, when the link motor control value is U _M , the U _M is calculated by the following equation (23).
U _M = G _MP U (23)
Note that _GMP is a motor control proportional gain, and the value of _{GMP is} a value set based on experiments or the like, and is stored in the storage means in advance.

Finally, the link motor control unit 42 outputs the link motor control value _UM to the link motor 25 (step S43), and ends the link motor control process.

  Although the link motor control process has been described here as proportional control, that is, P control, it may be PID control.

  Next, the operation of the steering control process, which is a part of the vehicle body control operation in turning, will be described.

  FIG. 14 is a diagram for explaining the steering angle when the vehicle speed sensor value is abnormal in the embodiment of the present invention, FIG. 15 is a diagram showing the relationship between the vehicle speed and the acceleration in the embodiment of the present invention, and FIG. The figure which shows the vehicle speed calculated based on the acceleration correction value in embodiment of invention, FIG. 17 is a figure explaining the lateral acceleration by steering in embodiment of this invention, FIG. 18 is variable in embodiment of this invention FIG. 19 is a flowchart showing the operation of the steering control process in the embodiment of the present invention. 14, (a) is a diagram showing a case where the vehicle speed sensor value is normal, (b) is a diagram showing a case where the vehicle speed sensor value is abnormal, and in FIG. 15, (a) is a time of the vehicle speed. The figure which shows a change, (b) is a figure which shows the time change of an acceleration.

When the steering control process in the present embodiment starts the steering control process, first, the steering angle sensor value δ _st that is the value of the steering wheel angle detected by the steering wheel angle sensor 62 is acquired (step S51). The steering wheel angle is a steering angle command input by an occupant operating the steering bar 41a.

Subsequently, the steering control unit 66 performs a filter process on the steering wheel angle sensor value δ _st (step S52). The filter process is a process using a low-pass filter similar to the filter process in the link angular velocity estimation process, and an IIR filter or FIR filter generally used as a band-pass filter can be used. A simple low-pass filter of the system may be used.

  Subsequently, the steering control unit 66 acquires a vehicle speed sensor value ν that is a value of the vehicle speed detected by the vehicle speed sensor 54 (step S53). This is because the steering angle command input by the occupant operating the handle bar 41a is reduced according to the vehicle speed to control the steering angle of the wheel 12F. More specifically, the variable reduction ratio is set based on the vehicle speed, and the steering angle target value of the wheel 12F as the steering wheel that is changed by the steering motor 65 as the steering actuator device is changed according to the variable reduction ratio. This is because the steering angle sensor value as the input steering angle command is reduced. The variable reduction ratio is determined so as to increase as the vehicle speed increases.

  Incidentally, the vehicle speed sensor value ν may not accurately indicate the actual vehicle speed. For example, when the occupant tries to decelerate by operating the brake lever during or before turning, one or more of the wheels 12F, 12L, and 12R are locked depending on the amount of operation of the brake lever and the surface condition of the road surface 18. There is a case. In such a case, the vehicle speed sensor value ν is zero or an extremely low value close to it, but since the vehicle 10 has not stopped running, the actual vehicle speed is higher than the vehicle speed sensor value ν. As described above, the steering control unit 66 sets the variable reduction ratio based on the vehicle speed sensor value ν, and reduces the steering angle target value with respect to the steering wheel angle sensor value according to the variable reduction ratio. When the value ν is lower than the actual vehicle speed, as shown in FIG. 14B, the steering angle target value increases, and as a result, the steering angle of the wheel 12F increases.

In FIG. 14, ν _real represents the actual vehicle speed, and ν _sensor represents the vehicle speed sensor value. Further, δ _st indicates a steering angle sensor value, and δ indicates a steering angle target value. FIG. 14A shows the steering angle of the wheel 12F when the actual vehicle speed is equal to the vehicle speed sensor value, and FIG. 14B shows the wheel 12F when the vehicle speed sensor value is lower than the actual vehicle speed. The steering angle is shown. FIG. 14 shows that when the vehicle speed sensor value is lower than the actual vehicle speed, the steering angle of the wheel 12F increases even at the same vehicle speed. If the steering angle of the wheel 12F is increased when the vehicle speed is high, the stability of the vehicle 10 is reduced.

  Therefore, in the present embodiment, the steering control unit 66 differentiates the acquired vehicle speed sensor value ν to calculate the longitudinal acceleration, so that the calculated longitudinal acceleration value falls within a predetermined range set in advance. The vehicle speed sensor value ν is replaced with the corrected longitudinal acceleration value, that is, the vehicle speed value calculated from the corrected acceleration value. More specifically, it is determined whether or not the value of the longitudinal acceleration is within the predetermined range, and if it is within the predetermined range, the acquired vehicle speed sensor value ν is used as it is and is not within the predetermined range. In this case, it is determined that the vehicle speed sensor value ν is abnormal, and the vehicle speed sensor value ν is replaced with a vehicle speed value calculated from the corrected acceleration value.

  A specific description will be given based on the example shown in FIGS. FIG. 15A is a diagram showing a change in vehicle speed over time, a solid line A indicates a vehicle speed sensor value ν, and a broken line B indicates an actual vehicle speed. FIG. 15B is a diagram showing the temporal change of the longitudinal acceleration calculated by differentiating the vehicle speed sensor value ν, the broken line C shows the calculated acceleration, and the solid line D shows the corrected longitudinal acceleration. E indicates a predetermined range set in advance, and C1 and C2 indicate accelerations of portions not included in the predetermined range E. Further, FIG. 16 is a diagram in which the time change of the vehicle speed calculated from the corrected acceleration value is superimposed on FIG. 15A, and the broken line F indicates the vehicle speed calculated from the corrected acceleration value.

  As indicated by the broken line B, even if the vehicle speed gradually decreases to zero, one or more of the wheels 12F, 12L, and 12R are locked depending on the operation amount of the brake lever and the surface state of the road surface 18. In such a case, the vehicle speed sensor value ν may suddenly decrease as indicated by the solid line A. In the example shown in FIG. 15 (a), the vehicle speed sensor value ν overshoots and becomes negative, then increases due to the reaction, and then converges to zero.

The longitudinal acceleration calculated by differentiating the vehicle speed sensor value ν that changes as indicated by the solid line A changes as indicated by the broken line C. If the traveling vehicle 10 is normally decelerated, the longitudinal acceleration value cannot be positive, and even if it is negative, it does not become a very large absolute value. Therefore, the predetermined range E is set in advance so that the upper limit value is zero and the lower limit value is a _lim . The value of a _lim is, for example, minus 1 [G].

The longitudinal acceleration of the portion C1 below the predetermined range E is corrected to be a _lim which is the lower limit value of the predetermined range E, and the longitudinal acceleration of the portion C2 above the predetermined range E is the upper limit of the predetermined range E. It is corrected to be a value. That is, the longitudinal acceleration is corrected so that the value thereof falls within the predetermined range E. As a result, a corrected longitudinal acceleration value as indicated by the solid line D, that is, a corrected acceleration value can be obtained.

  Further, when the vehicle speed is calculated by time integration of the corrected acceleration value, it is as indicated by a broken line F in FIG. In this way, it can be seen that the vehicle speed calculated from the corrected acceleration value is approximate to the actual vehicle speed, although it does not match.

Therefore, the steering control unit 66 makes a ν _old call (step S54). ν _old is a vehicle speed sensor value ν stored when the vehicle body tilt control process is executed last time. Note that ν _old = 0 in the initial setting.

Subsequently, the steering control unit 66 acquires a control cycle T _S (step S55).

Then, the steering control unit 66, by differentiating the vehicle speed sensor value [nu, calculates the longitudinal acceleration a _l (step S56). Here, when the differential value of the vehicle speed sensor value ν is dν / dt, the longitudinal acceleration _al is calculated by the following equation (24).
a ₁ = dν / dt = (ν−ν _old ) / T _S (24)
Subsequently, the steering control unit 66 obtains a drive motor torque command value T as a torque command value for operating the rotary drive device 51 from the drive motor control unit 57 (step S57), and the drive motor torque command value. It is determined whether T is greater than or equal to zero (step S58).

  The drive motor torque command value T is a control value for controlling the operation of the rotary drive device 51 that rotates the left and right wheels 12L and 12R, so that the state of acceleration or deceleration of the vehicle 10, that is, the vehicle state is accurately determined. It can be thought of as representing. If the value of the drive motor torque command value T is equal to or greater than zero, that is, zero or positive, it means that the vehicle is accelerating, and if it is negative, it means that the vehicle is decelerating. Therefore, it can be accurately determined whether or not the vehicle 10 is decelerating based on whether or not the drive motor torque command value T is equal to or greater than zero.

When the drive motor torque command value T is not zero or more, that is, minus, it can be determined that the vehicle 10 is decelerating. In this case, the steering control unit 66 determines whether the longitudinal acceleration _al is greater than zero, that is, whether it is positive (step S59). When the longitudinal acceleration a _l is positive, corresponds to the portion C2 of the example shown in FIG. 15 (b), i.e., since than exceeds the predetermined range E, the steering control unit 66, the front-rear direction The acceleration a _l = 0 is set (step S60). That is, the longitudinal acceleration _al is corrected so as to be the upper limit value of the predetermined range E as a predetermined limit value. If the longitudinal acceleration _al is not positive, the longitudinal acceleration _al is not corrected so as to be the upper limit value of the predetermined range E.

Then, the steering control unit 66, the longitudinal acceleration a _l is equal to or less than a _lim, that is, whether it is less than the lower limit of the predetermined range E (Step S61). The longitudinal case direction acceleration a _l is less than the lower limit of the predetermined range E, corresponding to the portion C1 of the example shown in FIG. 15 (b), i.e., since than below the predetermined range E, the steering control The unit 66 sets the longitudinal acceleration a _l = a _lim (step S62). That is, the longitudinal acceleration _al is corrected so as to be the lower limit value of the predetermined range E as a predetermined limit value. When the longitudinal acceleration a ₁ is not less than a _lim , the longitudinal acceleration a ₁ is not corrected so as to be the lower limit value of the predetermined range E.

Subsequently, the steering control unit 66 corrects the vehicle speed sensor value ν (step S63). In this case, the vehicle speed sensor value ν is corrected by the following equation (25).
_{ν = ν old + a l T} S ··· formula (25)
And the steering control part 66 is preserve | saved as (nu) _old = (nu) (step S64). That is, the vehicle speed sensor value ν corrected at the time of execution of the vehicle body tilt control process is stored in the storage unit as ν _old .

Subsequently, the steering control unit 66 acquires the steering wheel angle limit value δ _stlim (step S65). The steering wheel angle limit value δ _stlim is the maximum steering angle command value that can be input by the occupant operating the handle bar 41a, that is, a value indicating the maximum turning angle of the handle bar 41a. Is a physical limit value set in advance based on

Note that if the drive motor torque command value T is determined to be greater than or equal to zero and is equal to or greater than zero, the vehicle 10 is not decelerating. Get the value δ _stlim .

Subsequently, the steering control unit 66 acquires the link angle limit value η _lim (step S66). The link angle limit value η _lim is the maximum value of the link angle that can be taken by the link mechanism 30 that tilts the vehicle body, and is a physical limit value set in advance based on the structure of the link mechanism 30 or the vehicle body. The limit value is set in advance so as to correspond to the upper limit value of the tilt angle that can maintain the stability of the vehicle body even when the vehicle is tilted.

Then, the steering control unit 66 obtains the wheel base L _H (step S67).

Subsequently, the steering control unit 66 sets a variable reduction ratio γ as a steering reduction ratio (step S68). The variable reduction ratio γ is a ratio of a steering wheel angle, that is, a steering wheel sensor value δ _st and a steering steering angle target value δ ^*. The actual steering angle of the wheel 12F as a steering wheel is determined by the occupant. Is a coefficient that is set to maintain the stability of the vehicle body during turning even when the vehicle speed is increased by reducing the steering angle as a steering angle command input by operating. In the present embodiment, the variable reduction ratio γ is calculated as follows.

As shown in FIG. 17, assuming that the steering angle is δ and the turning radius is r, the vehicle speed ν and the centrifugal force a ₀ as the lateral acceleration acting on the vehicle body at the time of turning are expressed by the above equations (14) and (15 ).

From the formulas (14) and (15), the centrifugal force a ₀ acting on the vehicle body during turning is expressed by the following formula (26).
a ₀ = ν ² / r (26)
From FIG. 17, the turning radius r is expressed by the following equation (27).
r = L _H / tan δ Formula (27)
Here, since the link angle limit value is η _lim , the maximum centrifugal force a _max that can act on the vehicle body when turning, that is, the maximum centrifugal force value a _max that the vehicle body can withstand is given by the following equation (28). expressed.
a _max = g tan η _lim = ν ² / r (28)
In addition, g is a gravitational acceleration.

From the equation (28), the following equation (29) can be obtained.
r = ν ² / (g tan η _lim ) (29)
Here, the maximum value of the steering angle calculated from the vehicle speed ν and the link angle limit value η _{lim is} assumed to be δ _max . Further, the ratio of the steering wheel angle limit value δ _stlim and the maximum steering angle value δ _max is defined as the variable reduction ratio γ by the following equation (30).
γ = δ _stlim / δ _max (30)
Then, the variable reduction ratio γ is expressed by the following equation (31) from the equations (27), (29), and (30).
γ = δ _stlim / tan ⁻¹ (L _H / r)
= Δ _stlim / tan ⁻¹ (gL _H tan η _lim / ν ² ) (31)
Here, since the steering wheel angle limit value δ _stlim , the gravitational acceleration g, the wheel base L _H, and the link angle limit value η _lim are constants, the variable reduction ratio γ is determined according to the vehicle speed ν from the equation (31). You can see that it changes.

FIG. 18 shows the relationship between the variable reduction ratio γ calculated based on the equation (31) and the vehicle speed ν. 18 shows the steering wheel angle limit value δ _stlim : 45 degrees, the link angle limit value η _lim : 30 degrees, the center of gravity height: 0.7 [m], and the tread (between the ground contact points of the left and right wheels 12L and 12R). Distance): a result of calculation using the vehicle 10 of 0.5 [m] as a model.

  In FIG. 18, ◆ indicates the value of the variable reduction ratio γ when the tread is not considered, and Δ indicates the value of the variable reduction ratio γ when the tread is considered. As described above, the variable speed reduction ratio γ is a coefficient for reducing the actual steering angle of the wheel 12F with respect to the steering wheel angle in order to maintain the stability of the vehicle body during turning. If the intersection of the gravitational force vector extension line and the road surface 18 is between the ground contact points of the left and right wheels 12L and 12R, the balance of the vehicle body will not be lost. As a result, the variable reduction ratio γ can be set smaller. Therefore, Δ is smaller than ◆ at the same vehicle speed. Actually, when setting the value of the variable reduction ratio γ, it is desirable to set it within the range between ◆ and Δ.

  In FIG. 18, the curve indicated by the solid line indicates the minimum turning radius corresponding to the variable reduction ratio γ when the tread is not considered, and the curve indicated by the broken line is the variable reduction ratio when the tread is considered. The minimum turning radius corresponding to γ is shown.

  When the calculation is made based on the equation (31), the value of the variable reduction ratio γ becomes negative in a range where the vehicle speed ν is low (for example, a range of about 10 [km / h]). Therefore, in the range where the value of the variable reduction ratio γ is negative, it is desirable to set the value of the variable reduction ratio γ to +1 as shown in FIG.

Subsequently, the steering control unit 66 sets the steering angle target value δ ^* (step S69). The steering angle target value δ ^* is calculated by the following equation (32).
δ ^* = δ _st / γ Expression (32)
Finally, the steering control unit 66 outputs the calculated steering angle target value δ ^* to the steering motor control unit 67 (step S70), and ends the steering control process.

Thus, in the present embodiment, when the vehicle speed sensor value ν is abnormal, the vehicle speed ν is estimated based on the deceleration set to a predetermined limit value in advance, and the reduction ratio of the steering angle with respect to the steering angle command To control the steering actuator device. That is, when the value of the longitudinal acceleration a _l as the differential value of the vehicle speed sensor value ν is not within the predetermined range, the value of the longitudinal acceleration a _l is corrected so as to be within the predetermined range, and the corrected longitudinal acceleration a _The vehicle speed ν is replaced with the value of _l , that is, the vehicle speed value calculated from the corrected acceleration value, and the handlebar 41a as the steering device is operated based on the vehicle speed ν and the link angle η of the link mechanism 30 that tilts the vehicle body. The reduction ratio of the steering angle target value δ ^* of the steered wheel that is changed by the steering motor 65 as the steering actuator device with respect to the steering angle sensor value δ _st that is the steering angle value as the steering angle command inputted in this manner, that is, A variable reduction ratio γ is set as a steering reduction ratio.

Thus, even when one or more of the wheels 12F, 12L, and 12R are locked during deceleration, even when the vehicle speed sensor value ν is different from the actual vehicle speed value, the steering angle target value δ ^{Since *} does not become too large, the stability of the vehicle body can be maintained and the turning performance can be improved.

Further, since the actual steering angle of the wheel 12F is controlled using a value obtained by dividing the steering wheel angle sensor value _δst by the variable reduction ratio γ as a control target value, the vehicle speed ν Since the actual steering angle of the wheel 12F is set to an appropriate value in accordance with the inclination state of the vehicle body and the vehicle body, the vehicle body can be inclined in the turning direction in a stable state.

Furthermore, the variable reduction ratio γ is controlled according to the vehicle speed ν so that the link angle η does not exceed the link angle limit value η _lim . Therefore, even when the vehicle speed ν is high, the stability of the vehicle body can be maintained and the turning performance can be improved.

Further, the variable reduction ratio γ is controlled to increase as the vehicle speed ν increases. For example, as shown in FIG. 18, the value of the variable reduction ratio γ is changed according to the vehicle speed ν. Thereby, the steering angle target value δ ^* can be appropriately controlled.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

  The present invention can be used for a vehicle having at least a pair of left and right wheels.

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Boarding part 12F, 12L, 12R Wheel 20 Main-body part 25 Link motor 30 Link mechanism 41a Handle bar 54 Vehicle speed sensor 65 Steering motor

Claims (3)

A vehicle body including a steering unit and a main body unit coupled to each other;
A wheel rotatably attached to the steering unit, and a steerable steering wheel for steering the vehicle body;
Non-steering wheels that are rotatably attached to the main body and are not steerable;
A steering device for inputting a steering angle command;
A vehicle speed sensor for detecting the vehicle speed;
A link mechanism for tilting the steering part or the main body part in a turning direction;
An inclination actuator device for operating the link mechanism;
A steering actuator device for changing a steering angle of the steered wheel based on a steering angle command input from the steering device;
A control device for controlling the tilt actuator device and the steering actuator device;
When the value of the vehicle speed detected by the vehicle speed sensor is abnormal, the control device estimates the vehicle speed based on a deceleration set in advance to a predetermined limit value, and reduces the steering angle with respect to the steering angle command. And controlling the steering actuator device.   The said control apparatus judges that the value of the said vehicle speed is abnormal, when the differential value of the vehicle speed which the said vehicle speed sensor detected exceeds the upper limit value or lower limit value of the predetermined range preset. Vehicle.   The vehicle according to claim 2, wherein the predetermined range is set such that an upper limit value is zero and a lower limit value is a negative value.

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